With the recent increasing processing rates of notebook PCs, the amount of heat diffused from their heat producing components, such as CPUs, hard disk drives, and graphics chips has been increasing. Such heat producing components, however, cannot be sufficiently cooled by conventional components, such as a heat sink, a heat pipe, and a cooling fan.
Conventionally, it is known that a notebook PC employs a closed loop system constructed of a tube that efficiently cools the CPU by circulating a liquid coolant in the tube from a heat absorbing element to a heat dissipating element and back to the heat absorbing element by means of an electric motor.
In Japanese Patent Application Laid-Open Publication (JP-A) HEI 7-243738 published on Sep. 19, 1995, Takeda et al. disclose an electronic apparatus cooling device using a magnetic fluid vibration motor. In this cooling device, a tube forms a closed loop, and a spherical magnetic member is caused to vibrate along the tube by means of an external magnetic field formed by an exciting current flowing through a coil in a driving section of the tube, to cause the liquid coolant in the tube to flow back and forth between the heat absorbing element and the heat dissipating element, whereby efficient cooling is achieved. The spherical magnetic element has an outer diameter which is substantially equal to an inner diameter of the tube. In an alternative configuration, the cooling device includes a tube of a closed loop having a branch tube equipped with such a driving section, and a one-way valve is provided on each side or one side of the branching section of the closed loop tube, wherein the liquid coolant is circulated by causing the spherical magnetic element to vibrate along the branch tube.
Forced cooling in common electronic apparatuses requires electric energy. In a battery operated electronic apparatus, however, it is desirable to reduce electric energy consumption significantly.
The inventors have recognized the need for an efficient energy-saving cooling system for an electronic apparatus.
An object of the present invention is to provide energy-saving cooling in an electronic apparatus.
Another object of the invention is to provide cooling in an electronic apparatus by circulating a fluid coolant by means of an energy-saving driving power.